South Perth, Western Australia
June 20, 2008
Canola growers whose plantings
have established poorly have been cautioned that reseeding or
patching out their crops were highly risky management options.
Department of
Agriculture and Food research officer Dr Mohammad Amjad said
such strategies were rarely profitable at this stage of the
season.
“Marginal soil water conditions at seeding and poor follow up
rains in May have resulted in poor and patchy crop establishment
in some areas in the central and northern agricultural regions.
Dr Amjad said decisions about re-seeding canola need to take
account of the potential of the existing stand and the potential
yield and quality of late seeded crops.
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Department research officer Dr Mohammad Amjad checks out
a patchy canola emergence at Perenjori. |
“Canola is a super flexible crop and normally compensates for
variation in plant establishment,” he said.
“Plant population between 50-90 plants per square metre should
achieve potential yield between 1.4 – 1.8 t/ha in most
circumstances.”
Research by the department on crop establishment showed patchy,
uneven and poor establishments of 20-40 plants/m2 were generally
adequate to achieve yield of 0.8 – 1.2 t/ha (80-90 per cent
yield of a uniform established crop with 50 plants/m2).
Plant population between 10 -20 plants/m2 the crop could still
be a viable option, albeit at a lower yield potential of about
0.4 -0.6 tonnes per hectare.
If canola emergence is between 4-6 plants/m2, the options of
reseeding canola or seeding with other crops, such as wheat, is
unlikely to be feasible or economical than keeping the status
quo as fallow.
“With triazine tolerant (TT) varieties comprising 90 per cent of
canola sowings, there are also not many crop patch-up options
left for the canola sown paddocks, as cereals can not be sown
because of high levels of triazine residues in the soil,” Dr
Amjad said.
He said it was important to count plant emergence in patchy
areas and make an allowance for late emerging plants, before
considering any future paddock management decisions for the
crop, such as nitrogen fertiliser.
“Generally patchy and poor stands of early sown canola are
agronomically and economically better than canola re-seeded
later in the season,” Dr Amjad said.
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